Thinning and site quality influence aboveground tree carbon stocks in yellow-poplar forests of the southern Appalachians

2010 ◽  
Vol 40 (4) ◽  
pp. 659-667 ◽  
Author(s):  
Tara L. Keyser

Little information exists regarding the effects of intermediate stand management activities (e.g., thinning) on C storage. This lack of information has created uncertainty regarding trade-offs between the benefits observed following thinning and C storage. Using long-term growth data, this study examines the effect of thinning on C storage while controlling for the effects of site quality in yellow-poplar ( Liriodendron tulipifera L.) forests throughout the southern Appalachian Mountains. In 1960, one hundred and eighteen 0.1 ha plots were established in yellow-poplar forests throughout the southern Appalachians and subsequently thinned to a randomly assigned residual basal area (RBA) (square metres per hectare). Carbon storage increased through time across all levels of RBA. RBA had a long-term effect on C storage with greater C storage occurring at greater RBA. On average-quality sites, thinning to 30 m2·ha–1 stored 84% more C than thinning to 10 m2·ha–1. At no time did plots with progressively lower RBA store more C than plots with progressively higher RBA. The results from this study provide information about the effects of intermediate silvicultural disturbance on C dynamics of the aboveground live tree pool in a complex landscape and may be used to inform decisions regarding trade-offs between active management and C storage.

1999 ◽  
Vol 23 (2) ◽  
pp. 69-77 ◽  
Author(s):  
Matthew H. Pelkki

Abstract In the central and southern Appalachian region of the United States, yellow-poplar is an important timber resource for the sawmill and composite wood industries. A dynamic programming optimization algorithm was used to evaluate financial returns from various thinning strategies on yellow-poplar stands. Improvement thinning was found to increase long-term returns more than any other thinning strategy on most combinations of site and stand quality. Only on a high site index stand with a stem distribution dominated by high quality trees was thinning from above found to be the most valuable strategy. When stands have low or average stem quality distributions, the typical rotation has one to two thinnings removing 20% to 35% of the basal area in each thinning. Timing of the initial improvement thinning ranges from 22-32 yr, and occurs earlier in higher site index stands. In stands of high stem quality, one to five thinnings removing 20% to 40% of the basal area are employed, and rotation length increases as production shifts to sawtimber. Stands with higher site index and stem quality distributions have higher numbers of thinnings. This research demonstrates the value of intermediate treatments in improving financial returns from yellow-poplar. South. J. Appl. For. 23(2):69-77.


2013 ◽  
Vol 164 (2) ◽  
pp. 37-46 ◽  
Author(s):  
Peter Bebi ◽  
Frank Krumm ◽  
Urs-Beat Brändli ◽  
Andreas Zingg

Dynamics of dense, uniform spruce-dominated mountain forests Dense, uniform stands have increased in spruce-dominated mountain forests during the last century and often cause silvicultural problems. During recent years, different research activities at Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) have addressed the development of such mountain forests with or without active management. For this, plots of the Swiss National Forest Inventory (NFI) between 1983/1985 and 2004/2006 have been analysed, dendroecological methods have been used to investigate competition and selfthinning processes and a reassessment of WSL long-term investigation plots has been conducted. NFI plots of stands which have already been dense during the first inventory period generally showed increasing basal area, stagnating stem numbers, strongly increasing amounts of deadwood and slightly increasing regeneration levels, both in managed and in unmanaged stands. Dendroecological field studies confirm that trees in the generally about 80 to 150 years old stands were strongly affected by competition-induced self-thinning and subsequent small-scale mortality processes few decades after stand initiation already. WSL long-term investigation plots generally confirm this dominance of relatively small-scale processes, but also show potential for silvicultural interventions, especially in early stages of self-thinning. According to the guidelines for silvicultural intervention in forests with protective functions (NAIS), an active management of later self-thinning stages with already short crowns and higher mortality should focus on stands where risks have to be considered as too high, based on hazard and damage potential and the size of the dense, uniform stands.


2021 ◽  
Author(s):  
Shane W. Stoner ◽  
Alison M. Hoyt ◽  
Susan Trumbore ◽  
Carlos A. Sierra ◽  
Marion Schrumpf ◽  
...  

AbstractManaged grasslands have the potential to store carbon (C) and partially mitigate climate change. However, it remains difficult to predict potential C storage under a given soil or management practice. To study C storage dynamics due to long-term (1952–2009) phosphorus (P) fertilizer and irrigation treatments in New Zealand grasslands, we measured radiocarbon (14C) in archived soil along with observed changes in C stocks to constrain a compartmental soil model. Productivity increases from P application and irrigation in these trials resulted in very similar C accumulation rates between 1959 and 2009. The ∆14C changes over the same time period were similar in plots that were both irrigated and fertilized, and only differed in a non-irrigated fertilized plot. Model results indicated that decomposition rates of fast cycling C (0.1 to 0.2 year−1) increased to nearly offset increases in inputs. With increasing P fertilization, decomposition rates also increased in the slow pool (0.005 to 0.008 year−1). Our findings show sustained, significant (i.e. greater than 4 per mille) increases in C stocks regardless of treatment or inputs. As the majority of fresh inputs remain in the soil for less than 10 years, these long term increases reflect dynamics of the slow pool. Additionally, frequent irrigation was associated with reduced stocks and increased decomposition of fresh plant material. Rates of C gain and decay highlight trade-offs between productivity, nutrient availability, and soil C sequestration as a climate change mitigation strategy.


2009 ◽  
Vol 33 (2) ◽  
pp. 77-80 ◽  
Author(s):  
Ralph L. Amateis ◽  
Harold E. Burkhart ◽  
Colleen A. Carlson

Abstract Analysis of covariance methods applied to long-term loblolly pine spacing trial growth data showed that the orientation of rows with regard to a particular azimuth direction had no significant impact on either basal area or dominant height growth through the age of 20 years. Results were consistent for a range of planting densities and spacings and across a range of ages that included very young ages before crown closure. These results suggest that for loblolly pine growing in the Piedmont and Coastal Plain areas of Virginia and North Carolina, the selection of row orientation at plantation establishment can be made based on criteria other than growth.


2005 ◽  
Vol 35 (1) ◽  
pp. 221-228 ◽  
Author(s):  
J G Bockheim ◽  
H Park ◽  
J Gallagher

This study was initiated in 1990 to determine the effects of simulated logging practices on long-term productivity of trembling aspen (Populus tremuloides Michx.). Treatments included three levels of biomass removal (entire aboveground woody biomass, control; control + coarse woody detritus, LS; and LS + forest floor, FF) and two levels of compaction (light compaction on winter skid roads, TRA; heavy simulated compaction with FF, COM). The study was conducted on a Typic Haplorthod and a Haplic Glossudalf of medium site quality (site index50 years = 21 and 23 m, respectively) on the Brule State Forest. Twelve years after treatment, the following results were noted: (1) there were no significant differences in aspen height growth among treatments at either site except for lower stocking, height, diameter, and basal area on heavily compacted plots (COM, forest floor removed before compaction) at the clay site; (2) there was considerable genotypic variation in aspen height growth; and (3) recovery of physical properties, as reflected by bulk density, occurred within 12 years of treatment but was not manifested by improved aspen growth. These results suggest that concern over long-term effects of intensified biomass removal and soil compaction should be matched by a concern over protection of the aspen gene pool in the upper Great Lakes region.


Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 556
Author(s):  
Mauricio Zapata-Cuartas ◽  
Bronson P. Bullock ◽  
Cristian R. Montes ◽  
Michael B. Kane

Intensive loblolly pine (Pinus taeda L.) plantation management in the southeastern United States includes mid-rotation silvicultural practices (MRSP) like thinning, fertilization, competitive vegetation control, and their combinations. Consistent and well-designed long-term studies considering interactions of MRSP are required to produce accurate projections and evaluate management decisions. Here we use longitudinal data from the regional Mid-Rotation Treatment study established by the Plantation Management Research Cooperative (PMRC) at the University of Georgia across the southeast U.S. to fit and validate a new dynamic model system rooted in theoretical and biological principles. A Weibull pdf was used as a modifier function coupled with the basal area growth model. The growth model system and error projection functions were estimated simultaneously. The new formulation results in a compatible and consistent growth and yield system and provides temporal responses to treatment. The results indicated that the model projections reproduce the observed behavior of stand characteristics. The model has high predictive accuracy (the cross-validation variance explained was 96.2%, 99.7%, and 98.6%; and the prediction root mean square distance was 0.704 m, 19.1 trees ha−1, and 1.03 m2ha−1 for dominant height (DH), trees per hectare (N), and basal area (BA), respectively), and can be used to project the current stand attributes following combinations of MRSP and with different thinning intensities. Simulations across southern physiographic regions allow us to conclude that the most overall ranking of MRSP after thinning is fertilization + competitive vegetation control (Fert + CVC) > fertilization only (Fert) > competitive vegetation control only (CVC), and Fert + CVC show less than additive effect. Because of the model structure, the response to treatment changes with location, age of application, and dominant height growth as indicators of site quality. Therefore, the proposed model adequately represents regional growth conditions.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1540
Author(s):  
Bence Fülöp ◽  
Bálint Pacsai ◽  
Judit Bódis

Semi-natural grasslands were previously established through traditional land use and maintained by active management, but their extension nowadays is declining rapidly, particularly in areas that also have tourism potential. In parallel, the conservation value of the remaining areas is increasing. The shore of Lake Balaton is a particularly good example, as Lake Balaton is an area highly affected by tourism, yet there have been valuable habitats able to survive and provide refuge for many vulnerable, protected species. Fortunately, we have reliable information about the vegetation of the area from two decades ago. Comparing these data with our recent surveys we investigated the changes in habitats and the distribution of protected plant species in connection with the active conservation treatments such as grazing or cutting. Our results show that in areas where treatments are still ongoing, protected plant species are more likely to survive, or even other species can appear, which is in clear contrast with conditions experienced in abandoned areas, where at least seven protected species have disappeared. According to our results, minor, but appropriately chosen and well-executed management interventions, can help in the long-term maintenance of species-rich habitats and improving the conservation status of threatened species.


2019 ◽  
Vol 11 (21) ◽  
pp. 6041 ◽  
Author(s):  
Zhang ◽  
Li ◽  
Buyantuev ◽  
Bao ◽  
Zhang

Ecosystem services management should often expect to deal with non-linearities due to trade-offs and synergies between ecosystem services (ES). Therefore, it is important to analyze long-term trends in ES development and utilization to understand their responses to climate change and intensification of human activities. In this paper, the region of Uxin in Inner Mongolia, China, was chosen as a case study area to describe the spatial distribution and trends of 5 ES indicators. Changes in relationships between ES and driving forces of dynamics of ES relationships were analyzed for the period 1979–2016 using a stepwise regression. We found that: the magnitude and directions in ES relationships changed during this extended period; those changes are influenced by climate factors, land use change, technological progress, and population growth.


1996 ◽  
Vol 26 (9) ◽  
pp. 1620-1628 ◽  
Author(s):  
Qiong Su ◽  
Ted D. Needham ◽  
David A. MacLean

Changing stand composition by increasing hardwood content has been suggested as a long-term method for reducing susceptibility and vulnerability of balsam fir (Abiesbalsamea (L.) Mill.) to spruce budworm (Choristoneurafumiferana (Clem.)). Twenty-five mixed balsam fir–hardwood stands were selected in northern New Brunswick, with five stands in each 20% hardwood class (0–20, 21–40%, etc.). Defoliation each year from 1989 to 1993 was significantly (p < 0.0001) related to hardwood content, with r2 ranging from 0.57 to 0.81. As hardwood content increased, defoliation of balsam fir decreased. From 1989 to 1992, the years of moderate to severe defoliation, balsam fir stands with <40% hardwoods sustained 58–71% defoliation, on average, versus 12–15% defoliation in stands with >80% hardwood. A generalized model combining hardwood content and the estimated defoliation in pure softwood stands in a given year explained 77% of the variation in defoliation over stands and years. This study indicated that mixed balsam fir–hardwood stand management, with hardwood content >40%, could substantially reduce losses during spruce budworm outbreaks. Further research is warranted to elucidate the mechanism involved, but our working hypothesis is that greater hardwood content increased the diversity or populations of natural enemies such as birds and parasitoids.


2021 ◽  
Vol 130 ◽  
pp. 108110
Author(s):  
Lindsey S. Roberts ◽  
Abigail B. Feuka ◽  
Erin Muths ◽  
Bennett M. Hardy ◽  
Larissa L. Bailey

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